xc 



General Results of the Makeestoun Observations. 



Table 82. — Diurnal Variation of the Relative Humidity of the Air, for each Astronomical Season 

 • and for the Year, deduced from the Observations of the Years 1843-6. 



Mak. 



Nov. 



Feb. 



May. 



Aug. 







Mak. 



Nov. 



Feb. 



May. 1 Aug. 







Mean 



Dec. 



March. 



June. 



Sept. 



Year. 



Mean 



Dec. 



March. 



June. 



Sept. 



Y 



ear. 



Time. 



Jan. 



April. 



July. 



Oct. 







Time. 



Jan. 



April. : July. 



Oct. 







li. m. 



12 10 



+ 0-013 



+ 0-061 



+ 0103 



+ 0-072 



+ 



-062 



h. m. 



10 



-0035 



-0090, -0-109 



-0-106 



-C 



)-085 



13 10 



+ -014 



+ -065 



+ 



105 



+ -075 



+ 



-065 



1 10 



- -043 



- 



107j- -118 



- 



122 



- 



-097 



14 10 



+ -012 



+ -069 



+ 



105 



+ -072 



+ 



•064 



2 10 



- ^044 



- 



110 - -112 



- 



130 



- 



•099 



15 10 



+ -014 



+ -065 



+ 



109 



+ -078 



+ 



-066 



3 10 



- -027 



_ 



106 



- ^112 



- 



120 



— 



•091 



16 10 



+ -017 



+ -064 



+ 



101 



+ -075 



+ 



-064 



4 10 



- ^009 



- 



090 



- -102 



- 



096 



— 



•074 



17 10 



+ -018 



+ -066 



+ 



087 



+ -072 



+ 



•061 



5 10 



+ -001 



- 



052 



- -079 



- 



058! 



— 



•047 



18 10 



+ -022 



+ -058 



+ 



062 



+ -064 



+ 



051 



6 10 



+ -003 



- 



027 



- •OSl 



— 



016 



— 



•023 



19 10 



+ -019 



+ -050 



+ 



023 



+ -052 



+ 



•036 



7 10 



+ ^003 



+ 



009 



- ^012 



+ 



018 



+ 



•004 



20 10 



+ -021 



+ -027 



- 



017 



+ -019 



+ 



•012 



8 10 



+ ^007 



+ 



028 i+ ^031 



+ 



038 



+ 



•026 



21 10 



+ .007 



- -010 



- 



054 



- -019 



- 



019 



9 10 



+ -009 



+ 



037 + ^059 + 



051 j 



+ 



•039 



22 10 



- -005 



- -054 



- 



077 



- -057 



- 



048 



10 10 



+ ^007 



+ 



053 + -078 + 



060 



+ 



•049 



23 10 



- -027 



- -073 





103 



- -085 





072 



11 10 



+ ^004 



+ -060^+ -088 + 



057 



+ 



-052 



188. Diurnal Variation of the Relative Humidity. — The following are the approximate epochs of maxima 

 and minima, as obtained from Table 82. 



"Winter, Nov., Dec, Jan., Maximum 7*" a.m. Minimum l*" 50™ p.m. 



Spring, March, April, May, 3^ a.m I*' 50^ p.m. 



Summer, June, July, Aug., 3*^ a.m l** 20"' p.m. 



Autumn, Sept., Oct., Nov., 3^ a.m 2'' 10" p.m. 



Year, S^^ a.m 1^ 40in p.m. 



The diurnal variation of relative humidity is nearly the inverse of that of the temperature of the air. 

 The mean relative humidity occurs at &^ 33"° a.m., and at 7"^ 1" p.m., the intei-\'al being 10*> 28«. 

 The range of the diurnal variation is least in winter, = 0-066 ; it is'greatest in summer, = 0-227 ; the 

 values of the range for spring being 0-179, and for autumn being 0-208. 



Atmospheric Pressure. 



189. The Mean Pressure of the Atmosphere at Makerstoun, 213 feet above the mean level of the sea, as 

 deduced from the observations in the 8 years 1842-9, =29-615 inches of mercury at 32° Fahrenheit, measured 

 on brass at 62° Fahrenheit ; with a probable error of 0'009 inch, each year's mean receiving an equal weio-ht. 



The mean pressure for any future year = 29-615 inches, with a probable error of 0-026 inch.* 



Table 83. — Monthly Means of the Atmospheric Pressure at Makerstoun, for the Years 1841-9. 



Month. 



1841. 



1842. 

 29-584 



1843. 



1844. 



1845. 



1846. 



1847. 



1848. 



1849. 



Mean of 8 Years. 



Height of 

 213 feet. 



Mean 

 Level 

 of Sea. 



Jan. 





in. 



29^357 



29-693 



29-512 



in. 



29-392 



in. 



29^604 



in. 



29-722 



in. 



29^508 



in. 



29-547 



in. 



29-786 



Feb. 





•611 



■499 



•321 



•704 



•617 



•625 



-194 



•819 



•549 



•788 



March 





•485 



•662 



•529 



•741 



•406 



•775 



•354 



•755 



•588 



•826 



April 





•946 



•487 



•805 



•642 



• 535 



•455 



•595 



•450 



•614 



•850 



May 





•626 



-620 



•980 



•703 



-648 



•599 



•770 



•796 



•718 



•951 



June 





•764 



•619 



•627 



•597 



•706 



•672 



•475 



•735 



•649 



•879 



July 





•665 



•635 



•625 



•622 



•556 



•794 



-619 



•583 



•637 



•865 



Aug. 



29-567 



•723 



•656 



-489 



•578 



•691 



•751 



•526 



•658 



•634 



•863 



Sept. 



•483 



•652 



•935 



•817 



•645 



•732 



•605 



•717 



•792 



•737 



•970 



Oct. 



-372 



•682 



•401 



-397 



•602 



•312 



•646 



•551 



•606 



•525 



•758 



Nov. 



•453 



•448 



•471 



-563 



•323 



•655 



•643 



•601 



•530 



•529 



•765 



Dec. 





•649 



•962 



-892 



•369 



-599 



•490 



•542 



•723 



•653 



•892 



Mean 





•653 



•609 



•645 



•586 



•571 



•638 



•555 



•663 



•615 



•846 



* All the observations are reduced to the mean of the flint and crown glass barometer of the Royal Society of London. In com- 

 paring these results with others reduced to the flint-glass barometer only, a correction of + 0003 in. should be applied. See iDtro- 

 duction 1844, page Iv. 



